Solar Power Water Pump, dual power

[jfreak53]

I need some help with a power setup, dual power I think is needed but I don't know how to dual power. I have a 373W water pump that I want to run from sun-up to sun-down. I have a 1'x3' solar panel, a charge controller that came with it and the other two panels I have, a truck battery and a 300W power inverter. Problem is the 300W inverter won't run the pump since it requires 373, every time I try the inverter shuts down.

Now this is a DIY project I am doing in a third world country, so most things I could run to the local Home Depot or radio shack for I cannot here. So it has to be a thing I can easily solve with basic electrical supplies. So considering I can't run the pump on batter power alone because of the inverter problem, how would I set it up to run dual power, part from the battery and part from the local electrical supply at the house?

Unless someone can offer a suggestion to get the inverter working? Thanks for any help you can give me on this problem, I'm at my wits end. If I was in the states $200 and I would have a low power solar DC water pump that runs direct and has it's own solar panel ha ha. But I'm not ha ha.

[Naptown]

Unfortunately you are out of luck
The motor will draw up to 5 times its running current on start up so the inverter is way undersized.
Secondly the panel you have is at most 80 or 90 watts probably less.
You will kill the battery in very short order as there is not enough power from the panel to even keep
up with the running motor.
So to make that system run even marginally you would need at least a 1000 watt inverter. and about 600W of
PV panel to account for losses.
Probably best to just hook it up to the grid. Sorry for the bad news but good luck.

[Mike90250]

Unfortunately you are out of luck
The motor will draw up to 5 times its running current on start up so the inverter is way undersized.
Secondly the panel you have is at most 80 or 90 watts probably less.
You will kill the battery in very short order as there is not enough power from the panel to even keep
up with the running motor.
So to make that system run even marginally you would need at least a 1000 watt inverter. and about 600W of
PV panel to account for losses.
Probably best to just hook it up to the grid. Sorry for the bad news but good luck.

ditto.

Except, you should try to measure the power draw of the pump, if you have any meter that can do that. (Kill-a-watt, or clamp on AC meter) That will give you a better idea of the power draw than just the tag on the motor, which can vary a lot with load.

[jfreak53]

Understood, thanks for all the info, great help. Now would it be possible to dual power as I was stating? Using all 3 panels and somehow allow part of the energy to be drawn from battery and part from elec to drop cost some? If so, know of any good tuts on this?

[Mike90250]

how would I set it up to run dual power, part from the battery and part from the local electrical supply at the house?.

The best way, is to use a Grid Tie inverter, which is matched to your PV panels. Hooks to the grid, no batteries.

But, spending $1,000 for a inverter, which will save you $20 a year in electric, is not very cost effective. The little panels you have, just do not produce much electricity.

To salvage what you have, I'd just rig up a small 12V lighting system, and maybe use the inverter to keep a laptop and wireless running thouugh a power outage.

[Naptown]

Again no
The inverter you have is most likely for a stand alone system (off grid) and will not be able to be tied into the grid as such. You would need to find a grid tie inverter for that application that would sync to the grid. At that point just eliminate the battery as it would no longer be needed and your production will go up.
The only way to do what you want is to install a transfer switch for the pump that will isolate the grid from the PV system and allow you to switch from one power source to the other.
Now if you are serious about this make sure you get an inverter that is both the correct size and a pure sine wave. Motors tend to not like modified sine waves and the watts draw will go up making a bad situation worse.

[jfreak53]

Ok thanks for all the info. Yeah I just checked, the cheapest inverter I can find of those is $200 on amazon, don't even know if it would work for the use I am giving it:

http://www.amazon.com/Ensupra-Grid-Tie-Inverter-550W/dp/B0044M8J5S

But at that price I mise well just buy a solar powered low output water pump, cost the same. Ok thanks for all your help, very informative.

[SteveC]

Would you be able to make use of a much smaller pump? Probably not, I know, but what you have will not work at all.

[Sunking]

Jfreak what you need to know is when you go from commercial power to stand alone solar, you are going to pay 10 to 15 times more for power the rest of your life all up front in cash in 5 year increments as you replace the batteries.

You mentioned a 370 watt pump from Sun Up to Sun Down so I assume 12 hours per day. That would require 4.4 Kwh per day which is a huge number for a solar off grid system. You are looking at $13K to $16,000 up front in cold hard cash. Just pay your 50-cents per day to the power company, it is a heck of a bargain you cannot beat.

[jfreak53]

Would you be able to make use of a much smaller pump? Probably not, I know, but what you have will not work at all.

That's what I was wondering if by lowering the pump I could run it by getting a smaller pump. Out of curiosity what could I run off of the 3 panels and a battery? What would be the max volts and wattage?

Thanks for all the help here with a beginner.

[russ]

That's what I was wondering if by lowering the pump I could run it by getting a smaller pump. Out of curiosity what could I run off of the 3 panels and a battery? What would be the max volts and wattage?

Thanks for all the help here with a beginner.

You need to say what the ratings of the panels are.

Lowering the pump? You mean deeper into the well?

[jfreak53]

The ratings are above in the thread, someone came up with a basic based on their size, each panel I think they said was 60-80 output. Not deeper into the well, the electricity consumption.

I found these nice little pumps:

http://www.altestore.com/store/Solar-Water-Pumps/Surface-Solar-Pumps/Shurflo-Surface-Pumps/Shurflo-2088-343-135-12V-Ag-Pump/p1086/

But I am currently looking for them down here to see if I can find them. I did find shurflo down here, but not that pump, so I am looking for the distribuidor.